Decagon vs Sierra
Both are quote-only American vendors selling AI agents to large brands across chat, voice and email. Decagon lets you choose a per-conversation or per-resolution rate and adds always-on quality monitoring that also covers human agents. Sierra charges by outcome and lists more than 40 pre-built integrations. The decision turns on which meter and which supervision tooling suit your team.
Niels AbrahamsenAnalyst, Security & Infrastructure
Tomasz Wierzbicki
Elena MarchettiVendors can pay for visibility on this site; it never changes what we say about a product. How that works.
Choose Decagon ifyou want to choose between a per-conversation and a per-resolution rate, and you want one monitoring tool that scores both AI and human conversations against your own criteria.
Choose Sierra ifyou prefer to pay for agreed outcomes such as a resolved conversation or a saved cancellation, and you want pre-built integrations plus a test suite that catches regressions before each release.
Decagon and Sierra side by side
| Decagon | Sierra | |
|---|---|---|
| Our AI customer service rank | #12 of 15 | #13 of 15 |
| Established in | United States | United States |
| Pricing | Quoted; per conversation or per resolution | Quoted per outcome |
| List price, 30 September 2026 | Quote only | Quote only |
| Free tier | — | — |
| Open source | — | — |
| Self-hostable | — | — |
| Built for | Support operations wanting generative answers with close human supervision built in | Consumer brands automating transactions such as returns and subscription cancellations |
| Not for | Buyers who need long vendor history or a published rate | Small teams or anyone needing a price without a sales process |
Both are reviewed in full in our AI customer service ranking: Decagon and Sierra.
Where they differ
Decagon 1 · Sierra 0 · open 4- 01
Answers from an untidy knowledge base
Both vendors use real conversations to improve what the agent knows. Decagon's Duet proposes improvements and new workflows from customer conversations, and each change needs human approval. Sierra's Agent Studio lets teams view and edit knowledge, identifies themes missing from the knowledge base and drafts articles from representative interactions. Neither vendor leaves poor content to fix itself, so this round is even.
Depends on the buyer
- 02
Doing things, not only answering
Sierra states that its agents take real-time action on a customer's behalf through more than 40 pre-built integrations and custom connectors. Decagon's Agent Operating Procedures connect to your support tools, pull live data and trigger workflows across systems, without a published count of connectors. Both act on back-end systems; Sierra gives the more specific account of how.
Depends on the buyer
- 03
Who steers the agent
Decagon has teams write Agent Operating Procedures in natural language, as they would write procedures for human staff, while engineers keep version control through Git. Sierra's Agent Studio is described as needing no code, with simulated conversations and a regression test suite before release. Both put control with your own team; the difference is the working style, not who holds the controls.
Depends on the buyer
- 04
Watching quality after launch
Decagon's Watchtower reviews conversations continuously against criteria you write in plain language, such as signs of frustration or privacy breaches, and it covers human agents as well as AI. Sierra offers observability into agent reasoning, tool calls and knowledge lookups, plus evaluations. For a support operations lead who wants one quality view across people and agents, Decagon goes further.
Edge: Decagon
- 05
The meter
Decagon offers two models: a fixed rate per incoming conversation, which it says most customers choose, or a higher rate per fully resolved conversation with no charge for escalations. Sierra prices by outcome, such as a resolved conversation or a saved cancellation, and says unresolved or escalated cases are in most cases free. Neither publishes a rate.
Depends on the buyer
When neither fits
Neither fits a small team, or one whose transcripts may not leave its own infrastructure. Fin publishes its price per resolution, so the cost is visible before any sales conversation, and Rasa has a free developer edition and can run entirely on your own servers.
Decagon or Sierra: questions
4 answersHow do Decagon and Sierra charge?
Both are quote-only. Decagon offers a fixed rate per conversation or a higher rate per resolved conversation, with no charge for escalations on the second model.
Sierra charges for agreed outcomes and says an unresolved or escalated conversation is in most cases free. Get the outcome definition in writing from either.
Which channels do Decagon and Sierra cover?
Both go well beyond web chat. Decagon lists chat, voice, email, SMS, WhatsApp and custom surfaces, in more than 70 languages. Sierra lists chat, SMS, WhatsApp, email, voice and ChatGPT, and describes its agents as multilingual. Voice and messaging are therefore available from either vendor.
Who uses Decagon and Sierra?
Both name large brands. Decagon's site lists Deutsche Telekom, American Airlines, Duolingo, Chime and Rippling among its customers. Sierra's lists Gap, SiriusXM, Hyatt, Wayfair, Rivian and SoFi. Ask each for a reference customer in your own industry and at your contact volume.
Does Sierra only charge for resolved conversations?
Mostly. Sierra describes outcome-based pricing in which a resolved conversation, a saved cancellation or an upsell can count as an outcome, and unresolved cases are in most cases free.
It also offers blended pricing, where routing or greeter-style interactions are billed by conversation count regardless of outcome.
Sources
Checked 30 September 2026- Decagon homepage: Decagon products, channels and named customers.
- Decagon Agent Operating Procedures page: natural-language procedures, Git versioning, triggering workflows across systems.
- Decagon Watchtower page: always-on monitoring of AI and human conversations against custom criteria.
- Decagon blog on pricing AI agents: per-conversation and per-resolution models, no charge for escalations.
- Decagon comparison page: Decagon's own claims on Duet, 70+ languages and channels.
- Sierra homepage: Sierra channels, outcome-based pricing and named customers.
- Sierra Agent Studio page: no-code building, knowledge tools, 40+ integrations, test suite.
- Sierra blog on outcome-based pricing: what counts as an outcome, unresolved and escalated cases, blended pricing.